This invention relates to a technique of remote copy between storage subsystems.
Lately, more and more computer systems are being run 24 hours a day, and are demanded to recover from a disaster in a shorter period of time. One of the technologies to meet the demand is remote copy, which does not use a computer in making a copy of a volume in a storage subsystem located on a remote site.
Remote copy enables a computer system to recover from a disaster quickly by switching from a primary volume (a volume from which data is copied) to a secondary volume (a volume to which data is copied) to resume service. A remote copy technique has been disclosed in JP 11-85408 A in which data is copied between different storage controllers without the intervention of a host computer.